AP Chemistry · Topic 1.7
Periodic Trends Practice
Part of Atomic Structure and Properties.(SAP-2.A)
Practice questions
27
Sample questions
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Sample 1difficulty 1/5
Group 2 elements (alkaline earth metals) typically form ions with charge
- Acheck_circle
+2
- B
-1
- C
-2
- D
+1
Why
Alkaline earth metals lose 2 electrons (ns²) to form +2 cations (Mg²⁺, Ca²⁺, Ba²⁺).
- A
Sample 2difficulty 1/5
Group 1 elements (alkali metals) typically form ions with charge
- A
-1
- B
+2
- Ccheck_circle
+1
- D
0
Why
Alkali metals lose their single ns¹ electron to form +1 cations (e.g., Na⁺, K⁺, Cs⁺).
- A
Sample 3difficulty 1/5
Group 17 (halogens) typically form ions with charge
- A
+7
- Bcheck_circle
-1
- C
-7
- D
+1
Why
Halogens gain 1 electron to complete their valence shell, forming -1 anions (F⁻, Cl⁻, Br⁻, I⁻).
- A
Sample 4difficulty 2/5
Going down group 1, atomic radius increases primarily because:
- A
Effective nuclear charge decreases significantly
- Bcheck_circle
Each successive atom adds a new principal energy level (shell)
- C
Electrons are added to a half-filled shell
- D
Atomic mass increases
Why
Each lower element has its valence electron in a higher n shell, which is farther from the nucleus.
- A
Sample 5difficulty 2/5
First ionization energies for Li, Be, B, C, N, O, F, Ne are plotted vs Z.
Why does IE₁ drop slightly from N to O even though Z increases?
- A
N has fewer protons than O.
- Bcheck_circle
Pairing in the 2p_x orbital introduces electron-electron repulsion, lowering IE.
- C
O has a half-filled p subshell.
- D
O is smaller than N.
Why
N has half-filled 2p (extra stability). O's fourth 2p electron must double up, raising repulsion and making it easier to remove.
- A